text: /*
   * drivers/extcon/extcon-adc-jack.c
   *
   * Analog Jack extcon driver with ADC-based detection capability.
   *
   * Copyright (C) 2016 Samsung Electronics
   * Chanwoo Choi <cw00.choi@samsung.com>
   *
   * Copyright (C) 2012 Samsung Electronics
   * MyungJoo Ham <myungjoo.ham@samsung.com>
   *
   * Modified for calling to IIO to get adc by <anish.singh@samsung.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   */
  
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/device.h>
  #include <linux/platform_device.h>
  #include <linux/err.h>
  #include <linux/interrupt.h>
  #include <linux/workqueue.h>
  #include <linux/iio/consumer.h>
  #include <linux/extcon/extcon-adc-jack.h>
  #include <linux/extcon.h>
  
  /**
   * struct adc_jack_data - internal data for adc_jack device driver
   * @edev:		extcon device.
   * @cable_names:	list of supported cables.
   * @adc_conditions:	list of adc value conditions.
   * @num_conditions:	size of adc_conditions.
   * @irq:		irq number of attach/detach event (0 if not exist).
   * @handling_delay:	interrupt handler will schedule extcon event
   *			handling at handling_delay jiffies.
   * @handler:		extcon event handler called by interrupt handler.
   * @chan:		iio channel being queried.
   */
  struct adc_jack_data {
  	struct device *dev;
  	struct extcon_dev *edev;
  
  	const unsigned int **cable_names;
  	struct adc_jack_cond *adc_conditions;
  	int num_conditions;
  
  	int irq;
  	unsigned long handling_delay; /* in jiffies */
  	struct delayed_work handler;
  
  	struct iio_channel *chan;
  	bool wakeup_source;
  };
  
  static void adc_jack_handler(struct work_struct *work)
  {
  	struct adc_jack_data *data = container_of(to_delayed_work(work),
  			struct adc_jack_data,
  			handler);
  	struct adc_jack_cond *def;
  	int ret, adc_val;
  	int i;
  
  	ret = iio_read_channel_raw(data->chan, &adc_val);
  	if (ret < 0) {
  		dev_err(&data->edev->dev, "read channel() error: %d\n", ret);
  		return;
  	}
  
  	/* Get state from adc value with adc_conditions */
  	for (i = 0; i < data->num_conditions; i++) {
  		def = &data->adc_conditions[i];
  		if (def->min_adc <= adc_val && def->max_adc >= adc_val) {
  			extcon_set_state_sync(data->edev, def->id, true);
  			return;
  		}
  	}
  
  	/* Set the detached state if adc value is not included in the range */
  	for (i = 0; i < data->num_conditions; i++) {
  		def = &data->adc_conditions[i];
  		extcon_set_state_sync(data->edev, def->id, false);
  	}
  }
  
  static irqreturn_t adc_jack_irq_thread(int irq, void *_data)
  {
  	struct adc_jack_data *data = _data;
  
  	queue_delayed_work(system_power_efficient_wq,
  			   &data->handler, data->handling_delay);
  	return IRQ_HANDLED;
  }
  
  static int adc_jack_probe(struct platform_device *pdev)
  {
  	struct adc_jack_data *data;
  	struct adc_jack_pdata *pdata = dev_get_platdata(&pdev->dev);
  	int i, err = 0;
  
  	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	if (!pdata->cable_names) {
  		dev_err(&pdev->dev, "error: cable_names not defined.\n");
  		return -EINVAL;
  	}
  
  	data->dev = &pdev->dev;
  	data->edev = devm_extcon_dev_allocate(&pdev->dev, pdata->cable_names);
  	if (IS_ERR(data->edev)) {
  		dev_err(&pdev->dev, "failed to allocate extcon device\n");
  		return -ENOMEM;
  	}
  
  	if (!pdata->adc_conditions) {
  		dev_err(&pdev->dev, "error: adc_conditions not defined.\n");
  		return -EINVAL;
  	}
  	data->adc_conditions = pdata->adc_conditions;
  
  	/* Check the length of array and set num_conditions */
  	for (i = 0; data->adc_conditions[i].id != EXTCON_NONE; i++);
  	data->num_conditions = i;
  
  	data->chan = devm_iio_channel_get(&pdev->dev, pdata->consumer_channel);
  	if (IS_ERR(data->chan))
  		return PTR_ERR(data->chan);
  
  	data->handling_delay = msecs_to_jiffies(pdata->handling_delay_ms);
  	data->wakeup_source = pdata->wakeup_source;
  
  	INIT_DEFERRABLE_WORK(&data->handler, adc_jack_handler);
  
  	platform_set_drvdata(pdev, data);
  
  	err = devm_extcon_dev_register(&pdev->dev, data->edev);
  	if (err)
  		return err;
  
  	data->irq = platform_get_irq(pdev, 0);
  	if (!data->irq) {
  		dev_err(&pdev->dev, "platform_get_irq failed\n");
  		return -ENODEV;
  	}
  
  	err = request_any_context_irq(data->irq, adc_jack_irq_thread,
  			pdata->irq_flags, pdata->name, data);
  
  	if (err < 0) {
  		dev_err(&pdev->dev, "error: irq %d\n", data->irq);
  		return err;
  	}
  
  	if (data->wakeup_source)
  		device_init_wakeup(&pdev->dev, 1);
  
  	adc_jack_handler(&data->handler.work);
  	return 0;
  }
  
  static int adc_jack_remove(struct platform_device *pdev)
  {
  	struct adc_jack_data *data = platform_get_drvdata(pdev);
  
  	free_irq(data->irq, data);
  	cancel_work_sync(&data->handler.work);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int adc_jack_suspend(struct device *dev)
  {
  	struct adc_jack_data *data = dev_get_drvdata(dev);
  
  	cancel_delayed_work_sync(&data->handler);
  	if (device_may_wakeup(data->dev))
  		enable_irq_wake(data->irq);
  
  	return 0;
  }
  
  static int adc_jack_resume(struct device *dev)
  {
  	struct adc_jack_data *data = dev_get_drvdata(dev);
  
  	if (device_may_wakeup(data->dev))
  		disable_irq_wake(data->irq);
  
  	return 0;
  }
  #endif /* CONFIG_PM_SLEEP */
  
  static SIMPLE_DEV_PM_OPS(adc_jack_pm_ops,
  		adc_jack_suspend, adc_jack_resume);
  
  static struct platform_driver adc_jack_driver = {
  	.probe          = adc_jack_probe,
  	.remove         = adc_jack_remove,
  	.driver         = {
  		.name   = "adc-jack",
  		.pm = &adc_jack_pm_ops,
  	},
  };
  
  module_platform_driver(adc_jack_driver);
  
  MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
  MODULE_DESCRIPTION("ADC Jack extcon driver");
  MODULE_LICENSE("GPL v2");
  